The son of a world famous mystery writer, Jimmy Kudo, has achieved his own notoriety by assisting the local police as a student detective. He has always been able to solve the most difficult of criminal cases using his wits and power of reason.

Mori Kogoro solves the case! It is a busy day for the detective when he plans to meet a client and watch the new Okino Yoko drama series. His assignment is to decipher a suspicious text message written in code by the client's daughter. However, Mori finds out there is a cat in the office. It is Goro, a Russian Blue that belongs to Eri. While Eri has to Okinawa for a case and Ran and Conan go to school, Mori has to look after the cat. Mori becomes annoyed with Goro when gets cathair over the wash towel, knocks down an English-to-Japanese dictionary, plays with shoes, and goes into the video collection. But through these hints, Mori is able to figure our the coded message! It turns out Conan hid katsuobushi in several places so Goro could give hints to Mouri. In the end, Eri shows up to pick up Goro.

Inspector Misao Yamamura arrived to investigate. Conan also tries to gather clues to help, but is limited to what he can do when a sneaky Eisuke starts to spy and watch him. Conan has to use different tactics so he won't seem suspicious to him.

A man buys a ticket to see a movie, which is a sequel to another he and his friends have seen in the past. He gives his ticket to one of his friends, then leaves, but clues he has left behind leads Conan to believe that he has more on his mind. He plans to commit suicide, and plans frame his friend for it afterward.

The murder investigation narrowed to three suspects who were recent arrivals at the nearby inn. Conan deduced the culprit and the cause of the murder. He confronted the culprit at the murder site, but a shock waited him, Ran and Sonoko - the culprit was not alone! The culprit was a yakuza lieutenant who brought henchmen far too numerous for Ran to deal with alone. Makoto arrived in the nick of time, he and Ran fought them off until the police arrived.